Zinc Oxide Thin Films Research Articles

Synthesis and Characterization Studies of Pure and Co Doped ZnO Nano Thin Films

General Background: Thin-film technology is pivotal in advancing modern optoelectronic devices due to its ability to tailor material properties at the nanoscale. Specific Background: Zinc oxide (ZnO) and cobalt oxide (CoO) are prominent materials in this field, with doping techniques such as cobalt incorporation offering potential enhancements in film properties. Knowledge Gap: The impact of cobalt doping on the structural and optical properties of ZnO thin films remains inadequately explored, particularly concerning varying doping concentrations. Aims: Aims to elucidate the effects of cobalt doping on ZnO thin films' structural and optical characteristics, with concentrations of Zn0.6Co0.4O and Zn0.8Co0.2O compared to pure ZnO and CoO films. Results: Thin films were prepared via spin coating on glass substrates at 3000 rpm for 30 seconds. X-ray diffraction analysis revealed that pure ZnO films possess a hexagonal polycrystalline structure, whereas CoO films exhibit a cubic structure. Doping with cobalt resulted in a decrease in peak intensity at the (111) orientation and an increase in grain size. Optical measurements indicated enhanced transmittance and modified absorbance spectra with increased cobalt content, showing maximum absorbance at short wavelengths and diminished values in the visible region. Reflectivity increased with photon energy before decreasing at higher energies. Novelty: Cobalt doping significantly alters both structural and optical properties of ZnO films, with distinct changes in lattice constants, grain size, and optical behavior, suggesting a potential route for optimizing ZnO-based materials. Implications: Cobalt-doped ZnO films hold promise for improved performance in optoelectronic applications, such as solar cells and sensors, necessitating further research into diverse doping strategies to fully harness their technological potential. Highlights: Cobalt doping alters ZnO thin films' structural and optical properties. Spin coating method used at 3000 rpm for 30 seconds. Enhanced optical properties suitable for optoelectronic applications. Keywords: Thin films, Zinc oxide, Cobalt doping, Optical properties, X-ray diffraction

Characterization of RF-Sputtered ZnO Thin Film Coatings on Aluminum (Al6061): Microstructure, Wettability, Cavitation, and Corrosion Analysis

The study focuses on the characterization of Aluminum (Al-6061) coated with RF-sputtered Zinc Oxide (ZnO) thin film, aiming to understand the complex interactions between microstructure, wettability, cavitation resistance, and corrosion performance. The study involves the use of various analytical techniques such as Field Emission Scanning Electron Microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and water contact angle (WCA) measurements. The cavitation erosion testing has been conducted under various factors namely jet velocity (m/s), impingement angle (°), and stand-off distance (cm), respectively, and that too at various levels. Further, with the use of RSM, the study also contributes to the interplay in between factors and acquiring optimized results. Moreover, the findings of the study provide valuable insights into the effectiveness of the ZnO coating in enhancing corrosion resistance and reducing mass loss due to cavitation erosion. The study’s results offer significant implications for the engineering and design of protective coatings for Aluminum surfaces, with the potential to enhance durability and performance in various industrial applications.

Impact of oxygen vacancy on luminescence properties of dysprosium-doped zinc oxide thin films

Pristine and dysprosium-doped ZnO thin films, highly c-axis oriented, were grown on a c-Al2O3 substrate using the pulsed laser deposition technique. During the deposition process, the growth was impacted by changes in the oxygen partial pressure. The structural, optical, and compositional properties of the pristine and dysprosium-doped ZnO thin films were systematically characterized using various state-of-the-art experimental techniques. The crystallinity associated with these films was observed to be highly dependent on the oxygen partial pressure maintained during the growth process. An average optical transparency of more than ∼90% in the visible spectral range (i.e., 400–800 nm) was observed for all specimens. For doped specimens, expected intra-4fn emissions of (dysprosium) Dy3+ ions that emanated from the 4F9/2 energy state were observed in room-temperature photoluminescence spectra under direct excitation. The Jacobian-transformed wavelength-to-energy plot for Dy-doped ZnO thin films in the UV-Visible region revealed intriguing findings. Specifically, it depicted a prominent peak at 2.82 eV, indicative of the energy state of Dy3+ ions, alongside intense band-edge emission and various defect-related emissions. The intensity of these transitions was observed to depend on the oxygen partial pressure kept during deposition. An x-ray photoelectron spectroscopy analysis of the doped specimen confirmed the +3 oxidation state of dysprosium into the ZnO matrix. These results provide a promising approach for controlling the doping and growth strategy of Dy-doped ZnO thin films, thereby opening up a wide range of applications and enhancement for next-generation optoelectronic devices.

The figure of merit improvement of (Sn, Co)–ZnO sprayed thin films for optoelectronic applications

Nanocrystalline zinc oxide (ZnO) has garnered significant attention from researchers and industries due to its superior properties as an optoelectronic material, particularly in solar cells as a transparent electrode. Doping, especially with tin (Sn) and co-doping with tin and cobalt (Co), can refine its optoelectronic properties. In this manuscript, we report on the optoelectronic properties of undoped ZnO thin films, as well as those doped with Sn and/or Co, elaborated using a simple chemical pneumatic spray pyrolysis method on glass substrates. A 1 % Sn doping concentration was used, with Co doping concentrations of 0 %, 0.5 %, and 1 %. The effects of Sn and/or Co doping concentration on the structure, morphology, optical, and electrical properties of nanocrystalline ZnO were studied using X-ray diffractometer (XRD), Raman spectroscopy, Field emission scanning electron microscopy (FESEM), UV–Vis–NIR spectroscopy and Hall effect measurements. All the films studied exhibit wurtzite ZnO structures with a predominant (002) orientation and no secondary phase, as confirmed by X-ray diffraction (XRD) analysis. The Raman spectroscopy also reveals the presence of a wurtzite structure in all the films. The FESEM images reveal the kind and concentration of the dopants significantly influenced the surface morphology of the films. The elemental analysis with energy dispersive X-ray analysis (EDS) analysis successfully detected the doping of Sn and Co. The analysis of UV–Vis spectroscopy provide that the optical band gap for the undoped ZnO film is 3.25 eV. This band gap increases upon doping and co-doping, reaching a peak value of 3.30 eV for the Sn:Co (1 %:0.5 %) co-doped ZnO film. The ZnO film shows an improvement in the electrical resistivity upon doping and co-doping with low resistivity value of 1.95 × 10−2 Ω cm for the film (1%Sn, 0.5 % Co)–ZnO. The highest figure of merit (FOM) achieved is 1.41 × 10−4 Ω−1 for a ZnO thin film co-doped with (1 % Sn, 0.5 % Co). The existence of (1 % Sn, 0.5 % Co) film with improved optical gap, low electrical resistivity and high FOM supports its use in transparent conductive oxide applications.

Wedge-shape Al and Mg co-doped zinc oxide thin films: A Facile Route to achieve high thermoelectric power factor

Thin film thermoelectric technology has immense potential to become a next-generation power source for small-scale electronics. However, the rapid development of thin film thermoelectric still lacks a controllable structural design to improve the performance of thermoelectric devices for required temperature applications. This work presented a controlled thermoelectric design of ZnO-based thin films by Al and Mg co-doping using ALD. Herein, the Mg-doped ZnO sample exhibits the highest Seebeck coefficient of −311.83 μVK−1 at 500oC, while the maximum thermoelectric power factor of 3.68 μWcm−1K−2 is obtained at 300oC, which drops for higher temperatures. This decrease in power factor resulted from the reduction in electrical conductivity above 300oC. Similarly, the Al and Mg co-doped ZnO sample (Mg/Al ≈2 at%) exhibits a high thermoelectric power factor of 3.85 μWcm−1K−2 for ZnO based material due to its moderate electrical conductivity and Seebeck coefficient value at 325oC and behave monotonically for elevated temperatures. Scanning electron microscope (SEM) images show the formation of wedge-shaped structures for Al-incorporated samples, which helps to boost the overall thermoelectric performance. Additionally, we performed XRD, UV–Vis, Hall, and AFM analysis to get a deep insight into structural, optical, electrical, and surface features of the grown thin films and their linkage with the thermoelectric properties.

Synthesis and Characterization of Nanostructured Cerium-Doped Zinc Oxide Thin Films for Selective Nitrogen Dioxide Gas Sensing Applications

Zinc oxide thin films doped with cerium were synthesized through facile spray pyrolysis technique and subsequently characterized via an array of analytical methods, including X-ray diffraction, ultraviolet-visible diffused reflectance absorption spectroscopy, photoluminescence, scanning electron microscopy and energy-dispersive X-ray spectroscopy techniques. The operative mechanism of the semiconductor metal oxide gas sensors is predicated on the modulation of electrical conductivity in response to varying gaseous atmospheres, under the influence of disparate thermal conditions. The nitrogen dioxide gas-sensing performance of the films demonstrated a noteworthy gas response of 18% at an elevated temperature of 400°C for a concentration of 100 ppm, accompanied by rapid response and recovery times of 23 and 60 s, respectively.

An EPR study of point defects in zinc oxide thin films

We studied ZnO thin films deposited on glass slides by thermal evaporation in vacuum followed by heat treatment in open air or Ar flow. The samples were characterized using x-ray diffraction, Raman scattering, photoluminescence (PL), and electron paramagnetic resonance (EPR) spectroscopy. We observed a broad PL band in the visible region at spectral positions of 504 and 560 nm and a low-intensity band in the UV region at 390 nm. The EPR spectra display a clear first derivative structure at g=1.96 at temperatures below 200 K. The PL spectrum shows red-shifted valence to conduction band emission due to electron hole recombination through shallow surface states. We found an activation energy of E a = 4.2 meV using the Arrhenius plot and estimated concentrations of paramagnetic defects and spin–spin relaxation time constants of 1016 m−3 and 10–14 s, respectively.

In situ aluminum doped zinc oxide thin films by pulse electrodeposition for the all-electrodeposited cadmium-free copper indium diselenide solar cells

Pulse electrodeposition was used to produce aluminum doped zinc oxide (AZO) films, which were then used to construct an all-electrodeposited cadmium-free (Cd-free) Copper Indium Diselenide (CISe) solar cell. Aluminum was added into the films during the deposition process by positioning an Aluminum (Al) metal foil into the electrolyte. Energy Dispersive Spectrometry (EDS) elemental mapping confirmed the incorporation of Al into the films. According to X-Ray Diffraction (XRD) patterns, the aluminum doped zinc oxide films have a wurtzite hexagonal crystal structure, only with (002) planes indicating phase purity. The impedance analysis of the annealed device with electrodeposited aluminum doped zinc oxide revealed that it had better charge transfer resistance than the as-deposited device.

Enhancement of structural, optical, electrical, optoelectronic and thermoelectric properties of ZnO thin film via Ni doping and Ni-B co-doping

In this study, the effects of nickel (Ni) and boron (B) elements on the structural, optical, electrical, optoelectronic, and thermoelectric properties of zinc oxide (ZnO) material were investigated. Therefore, undoped ZnO, 3% Ni-doped ZnO (Zn0.97Ni0.03O), and 3% Ni-1% B co-doped ZnO (Zn0.96Ni0.03B0.01O) solutions were prepared by the sol gel method. The produced solutions were coated on glass and p-type Si substrates via dip coating and spraying methods in the form of thin films. We produce pure and n-type semiconductors in the form of nanodots which have wurtzite ZnO polycrystalline structure for all samples. Ni and B co-doped sample is morphologically, electrically and optically enhanced the ZnO material with 3.08 eV band gap, homogenous surface and the highest electrical conductivity. In addition, the best material among the three samples that can be used as a visible light-sensitive sensor is Zn0.96Ni0.03B0.01O under feedback voltage. Technologically, this material can be turned into a photodiode device in the form of Au/Zn0.96Ni0.03B0.01O/p-Si. While the obtained ideality factor of ZnO from the forward bias region decreases from 5.7 to 3.4, its barrier height increases from 0.636 eV to 0.667 eV and serial resistance of contact decreases from 121.6 × 103 Ω to 5.6 × 103 Ω with Ni and B co-doping. Ni doping thin film improves the photovoltaic, and thermoelectric properties of ZnO. Ni-doped ZnO sample can be studied in form of the thin films as a thermoelectric material due to its ZT value is nearly 1.73 × 10–4 at 650 K. Its thermoelectric performance is 13 times better than the that of pure ZnO for the same temperature values. The efficiency of Ni-doped ZnO sample as solar cell increases 10 times compared to pure ZnO. In addition to the production of materials with improved energy efficiency, economical products suitable for use in large areas have been obtained in this study.

Impact of aliovalent La-doping on zinc oxide – A wurtzite piezoelectric

The development of high-performance low-cost electroactive films for energy conversion and electronic device applications is a key goal of current advanced materials and condensed matter physics research. Here, using solution-based scalable chemical spray pyrolysis, high-quality electroactive lanthanum-doped zinc oxide (i.e., Zn1-xLaxO) thin films are grown on silicon substrates, and the impact of aliovalent lanthanum doping is investigated using a suite of microstructural, optical and nanoscale scanning probe microscopy techniques. The synthesized polycrystalline thin films show hexagonal wurtzite crystal structure with an increased unit cell volume, crystallite size, and conductivity with lanthanum doping up to 4 at.% beyond which the thin films (6 at.%), however, exhibit a change in dominant crystalline orientation from (101) to (002) plane. Concurrently, at this optimal dopant concentration of 4–6 at.%, the electromechanical performance is enhanced by about 20 %, and polarity-dependent nanoscale electronic transport behaviour is revealed. Our study, therefore, provides key insights into the impact of the rare earth aliovalent lanthanum dopant on the electroactive and electronic properties of low-cost, functional thin films for sustainable energy and sensing applications.

Effect of deposition temperature on growth of Zinc oxide Nanorods on Zinc oxide thin film for Optoelectronics and Sensing Applications

Effect of deposition temperature on growth of Zinc oxide Nanorods on Zinc oxide thin film for Optoelectronics and Sensing Applications

Synthesis of Mn doped nanostructured zinc oxide thin films for H2 gas sensing

Thin films of zinc oxide and (ZnO:Mn) with 1% and 3% concentrations were created at 400 °C by spray pyrolysis. According to X-ray diffraction (XRD) investigation, ZnO films are polycrystalline and have a cubic structure with a distinct peak in one direction (101). The grain size increases as manganese content rise, from 12.66 nm to 14.66 nm. While the strain (ε) for ZnO reduced after manganese doping, it decreased from 27.36 to 23.63. Surface topography and nanostructure study reveal that as the manganese (Mn) content of ZnO films increased, cluster grain size, average roughness, and root mean square roughness (Rrms) all significantly reduced. SEM images show substantial morphological changes from flat islands to spherical nano-grains post-manganese via Mn content. The average transmittance was >70% in the visible area for Undoped ZnO and 1, 3% Manganese doping optical transmittance demonstrates exceptional optical transparency. When doping levels are increased by 1% or 3%, the absorption coefficient rises. The optical band gap widens in ZnO: Mn film for allowed direct transition has been decreased from (3.32 to 3.21) eV. Results illustrate that the films' refractive index and extinction coefficient decreases with increasing Mn Doped. Hydrogen gas decreases resistance in ZnO films, suggesting p-type behavior. Doping with 3% Mn increases resistance. Decreased sensitivity with higher Mn content after hydrogen gas exposure indicates increased electrical resistance in the film.

Performance investigation of silicon nitride (SiNx) layer doped with twin thin films of gallium and zinc oxide for solar cell

Performance investigation of silicon nitride (SiNx) layer doped with twin thin films of gallium and zinc oxide for solar cell

Investigation of the effects of coating numbers of thin films and metal contact type on physical properties of undoped ZnO, Fe-doped ZnO, and Fe–B co-doped ZnO thin films

This study was designed for three purposes. The first objective was to examine the effects of iron (Fe) and boron (B) elements on the physical properties (structural, electrical, optical, and optoelectronic) of zinc oxide (ZnO) material. For this reason, pristine ZnO, 6% Fe-doped ZnO (Zn0.94Fe0.06O), and 6% Fe-4% B co-doped ZnO (Zn0.90Fe0.06B0.04O) thin films with different thicknesses (4, 6, 8, and 10 layers of coatings for each sample type) were produced using sol–gel dip coating and spraying method on glass and silicon (Si) substrates. In the second stage, we examined the effects of film thickness on optical, electrical, and optoelectronic properties for these three sample types. In the final stage, the MIS (metal/interlayer/semiconductor) structures were created using the three groups of samples produced as interlayers. Gold (Au) was initially applied as the metal contacts in these MIS structures. We investigated optoelectronic and electrical properties such as ideality factor, barrier height, and series resistance for all samples with Au contacts. Afterward, aluminum (Al) contacts were coated on the sample that yielded the best results with Au contacts, and the same properties were re-examined, thereby determining the effects of the contact material, especially on optoelectronic properties. All samples were produced as pure and wurtzite ZnO polycrystalline with preferred orientation along the (002) plane. Although Hall measurement results indicated that all sample groups were n-type semiconductors, the carrier density decreased from − 7.5 × 1013 for pristine ZnO to − 8.7 × 1011 with Fe–B co-doping. The irregular nanodots-shaped surface morphology of ZnO transformed into a homogeneous and smooth one by incorporating boron into the structure. In all sample groups except the 6% Fe-doped ZnO thin films, the band gaps of the thin films decreased as the film thickness increased. For pure ZnO and Fe-B co-doped ZnO sample groups, the band gap energy decreased from 3.245 to 3.215 eV, and from 3.540 to 3.180 eV, respectively, depending on the thicknesses of films. On the other hand, the band gap energy of only Fe–doped ZnO samples increased from 3.34 eV to 3.46 eV. It was observed that as the thicknesses of films increased, the ideality factor of Au/ZnO/p-Si, Au/Zn0.94Fe0.06O/p-Si, and Au/Zn0.90Fe0.06B0.04O/p-Si diodes increased, and the barrier heights of them decreased in the three sample groups. However, when we look at the average value of the electrical properties including all layers, we can say that the best results were obtained for the Fe–B co-doped sample group. Specifically, Fe–B co-doped ZnO sample with 6 layers of coating exhibited an ideality factor of 3.25, a barrier height of approximately 0.51 eV, and a serial resistance of 8.42 kΩ. The best performance as solar cell and photodiode was again obtained for this sample. While the solar cell efficiency of this sample (6 layers of coated Zn0.90Fe0.06B0.04O) was 0.04% with Au contacts, it increased to 0.08% with Al contacts.In summary, it was observed that the electrical, optical, structural, and optoelectronic (as solar cell and photodiode) properties of ZnO material were improved very well made with Al contact and 6 layers of coated Fe and B co-doping. Therefore, Zn0.90Fe0.06B0.04O sample may be promising material for optoelectronic devices.

P‐13: Excessive Oxygen induced Threshold Voltage Shifts in High Mobility Top‐Gate PrIZO TFTs

The top gate self‐alignment (TGSA) Praseodymium‐doped indium zinc oxide (PrIZO) thin film transistor (TFT) was fabricated with different process condition in our production line, and high field effect mobility of 40.83 cm2 V‐1 s‐1 was obtained by regulating the GI and ILD parameters. At the same time, the devices show excellent stability with PBTS of 0.52 V and NBTIS of ‐0.9 V, indicating its potential in overcoming the trade‐off between mobility and reliability.

Fabrication of zinc oxide and phosphorus optical thin films and comparison of their effect on silicon solar cell efficiency

Fabrication of zinc oxide and phosphorus optical thin films and comparison of their effect on silicon solar cell efficiency

97‐3: Late‐News Paper: Enhanced IGZO TFT Performance with Atomic Layer Deposition Parameter Optimization for Large OLED Displays

In this comprehensive study, we rigorously evaluated the applicability of amorphous indium gallium zinc oxide (a‐IGZO) thin films synthesized using atomic layer deposition (ALD) technology in the field of large‐area organic light‐emitting diode (OLED) TVs. The key term to display production is the distribution of device characteristics, and maintaining uniformity can improve productivity yield and product quality. The purpose of this paper is to present guidelines for early application in industry through the process variable exploration results of ALD deposition equipment. The process parameters studied are process pressure and oxygen partial pressure (PO2). We have secured a method to secure device characteristics suitable for display technology through the correlation between a‐IGZO thin film characteristics and device characteristics through corresponding parameters. Our empirical data strongly demonstrate that the threshold voltage (Vth) stabilizes near 0.0 V and consistently achieves device mobility exceeding 15 cm2/Vs. In particular, this study shows that the variability of the Vth characteristic, which is limited to a narrow range of less than ±0.1V, is greatly reduced, and the mobility dispersion is also greatly reduced to less than ±1cm2/Vs. A deeper analytical exploration revealed that the pivotal factors affecting device performance are closely related to oxygen vacancies (Vo) and their dynamic interactions with oxygen molecules. These results will improve the uniformity of device characteristics, and it is believed that the introduction of ALD technology into future display technology will demonstrate improvements in the performance and quality of display products.

Effects of Hydrogen Plasma Treatment on the Electrical Behavior of Solution-Processed ZnO Thin Films.

In this study, the effect of atmospheric hydrogen plasma treatment on the in-plane conductivity of solution-processed zinc oxide (ZnO) in various environments is reported. The hydrogen-plasma-treated and untreated ZnO films exhibited ohmic behavior with room-temperature in-plane conductivity in a vacuum. When the untreated ZnO film was exposed to a dry oxygen environment, the conductivity rapidly decreased, and an oscillating current was observed. In certain cases, the thin film reversibly 'switched' between the high- and low-conductivity states. In contrast, the conductivity of the hydrogen-plasma-treated ZnO film remained nearly constant under different ambient conditions. We infer that hydrogen acts as a shallow donor, increasing the carrier concentration and generating oxygen vacancies by eliminating the surface contamination layer. Hence, atmospheric hydrogen plasma treatment could play a crucial role in stabilizing the conductivity of ZnO films.

Investigation of structural, optical, electrical, thermoelectric and optoelectronic properties of undoped ZnO, Sb-doped ZnO and Sb–B co-doped ZnO thin films

Pure ZnO (Zinc oxide), 1 % Sb (antimony) doped ZnO (Zn0.99Sb0.01O), and 1 % Sb–1% B (boron) co-doped ZnO (Zn0.98Sb0.01B0.01O) solutions were prepared using the sol-gel method. These solutions were deposited as thin films on glass and Si (silicon) substrates via dip coating and spraying methods. In this study, doping ZnO with low amounts of Sb and B provided the conversion of the n-type semiconductor ZnO into a p-type semiconductor. The produced thin films were pure and had wurtzite ZnO polycrystalline structure. The nanodot morphology of ZnO turned into a mixture of nanodot and nanorod structures with only Sb doping. Moreover, the band gap energy of ZnO decreased from 3.26 eV to 3.24 eV with Sb doping and to 3.23 eV with Sb and B co-doping, accompanied by a decrease in optical transmittance depending on film thickness. All samples exhibited diode characteristics. According to the created Au/ZnO–Zn0.99Sb0.01O – Zn0.98Sb0.01B0.01O/Si diodes, it was understood that the ideality factor, barrier height, and serial resistance of ZnO material decreased with doping. Especially, the ideality factor, barrier height, and serial resistance of the ZnO sample decreased from 4.95, 6.80 eV, and 1.42 × 105Ω to 4.35, 6.25 eV, and 2.60 × 103Ω, respectively, with Sb and B co-doping. The photovoltaic performance of 1 % Sb-doped thin film increased 100 times compared to pure ZnO, reaching the efficiency from 0.006 to 0.600. However, the most suitable material for use as a photodiode was found to be the 1 % Sb–1% B co-doped sample. While the leakage current of this sample is around −8.0 × 10−5 A at −3 V under 100 mW/cm2 light, it is 9.5 × 10−8 A at −3 V in the dark. Furthermore, the 1 % Sb-doped thin film exhibited the best performance as a thermoelectric material at 600 K, achieving a figure of merit (ZT) of 0.00052. Overall, co-doping with Sb and B enhanced the optical, electrical, and structural (more homogeneous and less surface roughness) properties of ZnO, while improving its optoelectronic functionality such as photodiode. On the other hand, thermoelectric and solar cell properties of ZnO were enhanced with only 1 % Sb doping. A hybrid energy system containing thermoelectric and solar cells was produced cheaply and simply for wide application areas with this study. Moreover, with such a low doping amount, p-type material production was achieved, and important physical properties of the ZnO material were improved.

Impact of aluminium doping in magnesium-doped zinc oxide thin films by sputtering for photovoltaic applications

In this study, Mg-doped zinc oxide (MZO) thin films were deposited through radio frequency (RF) sputtering for different substrate temperatures ranging from room temperature (25 °C) to 350 °C. XRD analysis depicted that the higher substrate temperatures lead to increased crystallite size. From the UV–Vis spectroscopy, transmittance (T) was found approximately 95% and the optical band energy gap (Eg) was determined around 3.70 eV. Hall effect measurement system measured the carrier concentration and resistivity of all films in the order of 1014 cm−3 and 103 Ω-cm, respectively. Since the structural and optoelectrical properties of the MZO films were not significantly affected by the substrate temperatures, Aluminium (Al) was co-doped in the MZO film to improve structural and optoelectrical properties. As a result, the carrier concentration of Al doped MZO (AMZO) films was increased up to ~ 1020 cm−3 from ~ 1014 cm3 (MZO), and the resistivity was decreased up to ~ 10–1 Ω-cm from 103 Ω-cm (MZO) representing the significant changes in electrical properties without affecting the transmittance. This study opens a pathway for improving the MZO buffer layer that can enhance the cell performance of CdTe solar cells.Graphical abstract